Composite Material Lay-up Equipment

ABSTRACT

There is disclosed composite material lay-up equipment  10  for applying a plurality of individual lengths of elongate fibre reinforcement material  14  to an article  12 , the equipment  10  comprising: a support head  20 ; a cutting mechanism  22  carried by the support head  20  for severing a plurality of individual lengths of elongate fibre reinforcement material  14 . The cutting mechanism  22  comprises a plurality of cutting elements  60  coupled to and moveable with respect to the support head  20  and a cassette  65  removably attached to the support head  20  and having a plurality of corresponding counteracting elements  76  statically mounted thereto. Each cutting element  60  is displaceable relative to the corresponding counteracting element  76  to perform a cutting stroke in which the respective cutting and counteracting elements  60, 76  cooperate to sever a length of elongate fibre reinforcement  14  material extending through the nip formed between them.

BACKGROUND

The invention relates to composite material lay-up equipment forapplying lengths of elongate fibre reinforcement material to an article.

Fibre composite components are frequently used for applicationsrequiring a combination of light weight and strength, for example insports equipment and in aerospace components. Most fibre compositemanufacturing processes require successive layers of fibre reinforcementmaterial to be applied to an article or a mould in a lay-up process. Amatrix material is either pre-applied to the fibre reinforcementmaterial (pre-impregnated, or “pre-preg”) or is subsequently applied tothe reinforcement material before curing in or out of an autoclave.Recent manufacturing developments have allowed the lay-up process to beperformed automatically.

Three exemplary automatic composite manufacturing processes areAutomatic Tape Laying (ATL), Automatic Fibre Placement (AFP) andautomatic filament winding. Briefly, ATL relates to the application of atape comprising fibre reinforcement material to an article. The tapetypically comprises unidirectional fibres which are pre-impregnated withmatrix material (e.g. epoxy resin). Successive tape layers are typicallyapplied at different orientations from one another to form a plystructure. The tape is typically applied to the article by an applicatorroller.

In AFP, the fibre reinforcement material is applied to an article in theform of a “tow”, comprising a plurality of individual fibres, ormultiple “tows”. A “tow” may be a narrow width of tape slit from a widertape. AFP is typically more suitable for complex parts having a higherdegree of curvature or non-uniform curvature. The fibres are typicallypre-impregnated with matrix material or drawn through a bath of matrixmaterial. A course or series of “tows” is typically applied to thearticle by an applicator roller.

Automatic filament winding differs from AFP in that the articletypically functions as a rotating mandrel and the lay-up equipmenttypically traverses the mandrel to apply a tow of fibres in tension overthe mandrel surface. The angle at which the tow is laid over the mandrelcan be adjusted between successive passes of the mandrel such thatsuccessive layers lie at different orientations from one another to forma ply structure and to influence the properties of the component (e.g.improved compressive or tensile strength of the manufactured component).The tow of fibres is typically applied to the article by virtue oftensile forces in the tow between the mandrel and an applicator rollerof the lay-up equipment.

In all of the above processes it is necessary to sever (or cut) the towor tape of fibre reinforcement material (whether pre-impregnated or not)at the end of the process, or at the end of a stage in the process.

However, the cutting mechanisms used in known composite lay-up equipmentare bulky, which causes the equipment to be bulky at the tip region. Abulky tip region may limit the complexity of the articles to which fibrereinforcement material can be applied by the equipment, since it may notbe possible to manipulate the tip region over high curvature or otherhard-to-access parts of the article.

It is therefore desirable to provide improved composite lay-up equipmentwhich is less bulky in the tip region and to provide an improved cuttingmechanism for use with the equipment.

SUMMARY

According to an aspect of the invention there is provided compositematerial lay-up equipment for applying a plurality of individual lengthsof elongate fibre reinforcement material to an article, the equipmentcomprising: a support head; a cutting mechanism carried by the supporthead for severing a plurality of individual lengths of elongate fibrereinforcement material, the cutting mechanism comprising: a plurality ofcutting elements coupled to and moveable with respect to the supporthead; and a cassette removably attached to the support head and having aplurality of corresponding counteracting elements statically mountedthereto; wherein each cutting element is displaceable relative to thecorresponding counteracting element to perform a cutting stroke in whichthe respective cutting and counteracting elements cooperate to sever alength of elongate fibre reinforcement material extending through thenip formed between them. By “statically” it is meant that in use thecounteracting elements do not move to perform a cutting stroke.

The counteracting elements may be removably mounted to the cassette.

The cutting elements may be composed of a harder material than thecounteracting elements.

The cassette may comprise a plurality of guide ducts. Each counteractingelement may be disposed adjacent to a respective guide duct and may bearranged to guide the fibre reinforcement material away from the nipbetween the counteracting element and the corresponding cutting element.

Each guide duct may have a profile which tapers from a duct inletopening to a duct outlet opening.

The cassette may comprise an exit guide roller arranged to guide theindividual lengths of fibre reinforcement material away from thecassette.

Each counteracting element may have a cutting edge and each cuttingelement may have a cutting edge. The cutting edge of each cuttingelement may be inclined relative to the cutting edge of thecorresponding counteracting element such that in a cutting stroke thecutting element and the counteracting element cooperate in a scissoraction.

The cutting edge of each counteracting element may touch the pathfollowed by the cutting edge of the corresponding cutting element in acutting stroke.

The counteracting elements may be substantially planar. The cassette mayfurther comprise adjustment means capable of resiliently deflecting thecutting edge of each counteracting element towards the correspondingcutting element. The adjustment means may comprise a plurality ofadjustment screws, one for each counteracting element. Each adjustmentscrew may be turned so as to act on its counteracting element andthereby deflect the cutting edge.

The plurality of counteracting elements may be arranged side-by-side inat least one row. There may be two rows of counteracting elements. Thecutting edges of the first row of counteracting elements may face thecutting edges of the second row of counteracting elements. At least twocounteracting elements may be mounted to the cassette by a holder whichis removably mounted to the cassette. Each of the at least twocounteracting elements may be individually removably mounted to theholder. There may be two holders and each row of counteracting elementsmay correspond to a respective holder.

Each cutting element may be coupled to a separate elongate arm which maybe pivotable about a pivot axis. The elongate arms may be arranged tomove the cutting elements along an arcuate path during a cutting stroke.The cutting edge of each cutting element may be substantially parallelto the corresponding pivot axis. The cutting edge of each counteractingelement may be inclined with respect to the corresponding pivot axis.

According to an aspect of the invention there is provided a cuttingmechanism for severing elongate fibre reinforcement material incomposite material lay-up equipment, the cutting mechanism comprising acutting element and a counteracting element which cooperate to severfibre reinforcement material extending through the nip between them, thecutting element being mounted on an elongate arm which is pivotableabout a pivot axis spaced from the nip, to displace the cutting elementrelatively to the counteracting element to perform a cutting stroke, themechanism further comprising guide means arranged to guide the fibrereinforcement material through the nip in a feed direction transverse tothe pivot axis, and an actuation device for driving the elongate arm ina cutting stroke, the actuation device acting on the elongate arm at aposition away from the cutting element.

The actuation device may act on the elongate arm on one side of thepivot axis, and the cutting element may be mounted on the elongate armon the opposite side of the pivot axis. In configurations in which thepivot axis is offset from the elongate arm, the position of the pivotaxis is considered to be the normal projection of the pivot axis ontothe elongate arm.

The elongate arm may extend in a plane substantially perpendicular tothe pivot axis. The guide means may be arranged to guide the fibrereinforcement material along a guide path extending in a planesubstantially perpendicular to the pivot axis, and which may extendalong the elongate arm.

The guide means may comprise a guide channel having an outlet adjacentthe nip. The guide channel may be formed in the elongate arm. The guidechannel may be an enclosed channel over at least part of its length, inwhich case the outlet may be a slot. The guide channel may be providedwith a removable cover which may be pivotable at one end.

The cutting element may be situated such that a cutting edge of thecutting element is disposed at an end of the channel. The elongate armmay comprise a slot for receiving the first cutting element. The cuttingedge of the cutting element may provide a lip of the outlet. The cuttingelement may have a guide face flush with a surface of the channel whichterminates at the cutting edge of the cutting element.

The cutting element may be removably mounted on the elongate arm so asto be replaceable. The cutting element may comprise a hardened material.

The cutting element and the counteracting element may be arranged suchthat a cut formed in the fibre reinforcement material by a cuttingstroke extends transversely of the elongate fibre composite materialand/or substantially parallel to the pivot axis.

The cutting element and the counteracting element may be arranged suchthat fibre reinforcement material can pass between them in a directionperpendicular to a plane containing the pivot axis.

The cutting element and the counteracting element may have respectivecutting edges which are inclined relative to each other such that in acutting stroke the cutting element and the counteracting elementcooperate in a scissor action. The cutting element and the counteractingelement may have opposing cutting edges.

The cutting element and the counteracting element may have respectivecutting edges, and the cutting edge of the counteracting element maytouch the arcuate path followed by the cutting edge of the cuttingelement in a cutting stroke.

The elongate arm may be mounted to a structural support for pivotablemovement about the pivot axis, the pivot axis being fixed relative tothe structural support.

The cutting element may be one of a plurality of cutting elementsdisposed in an array and there may be at least one counteractingelement, each cutting element cooperating with the counteracting elementor with one of the counteracting elements to sever a respective lengthof fibre reinforcement material extending through a respective nipbetween the cutting element and the respective counteracting element.Each cutting element may be mounted on one of a corresponding pluralityof elongate arms which is pivotable about a pivot axis spaced from thenip, to displace the cutting element relatively to the, or therespective, counteracting element to perform a cutting stroke. The guidemeans may be arranged to guide the fibre reinforcement material throughthe nips in the feed direction which may be transverse to the or eachpivot axis. There may be at least one actuation device for driving theelongate arms in respective cutting strokes, and the or each actuationdevice may act on the elongate arms at positions away from therespective cutting elements.

The pivot axes of the array of elongate arms may be substantiallyparallel to one another. The pivot axes of the array of elongate armsmay be substantially coincident with each other.

The array may be one of at least two arrays disposed on opposite sidesof a plane extending through the pivot axis.

The elongate arms of the or each array may be arranged substantiallyside-by-side to form a row. There may be at least two rows of elongatearms and the elongate arms of each row may be arranged substantiallyside-by-side. There may be two arrays of elongate arms which mayconverge towards the distal end of the cutting mechanism.

At least one actuation device may be coupled to two or more elongatearms so as to drive them in unison. Each actuation device may act on asingle elongate arm. There may be a plurality of the actuation devices,which may be operable independently of one another.

At least one counteracting element may be arranged to cooperate with atleast two different cutting elements. Each counteracting element may bearranged to cooperate with a single cutting element.

According to an aspect of the invention there is provided a cuttingmechanism for severing elongate fibre reinforcement material incomposite material lay-up equipment, the cutting mechanism comprising aplurality of cutting elements and at least one counteracting element,each cutting element cooperating with the counteracting element or withone of the counteracting elements to sever a respective length of fibrereinforcement material extending through a respective nip between thecutting element and the respective counteracting element, each cuttingelement being mounted on a respective elongate arm which is pivotableabout a pivot axis spaced from the nip, to displace the cutting elementrelatively to the respective counteracting element to perform a cuttingstroke, the mechanism further comprising guide means arranged to guidethe fibre reinforcement material through the nips in a feed directiontransverse to the or each pivot axis, and at least one actuation devicefor driving the elongate arms in respective cutting strokes, the or eachactuation device acting on the elongate arms at positions away from therespective cutting elements.

According to an aspect of the invention there is provided compositematerial lay-up equipment for applying lengths of elongate fibrereinforcement material to an article, the equipment comprising a cuttingmechanism in accordance with any statement herein and a support headwhich carries the cutting mechanism.

The actuation device may be mounted to the support head. The actuationdevice may act between the support head and the elongate arm. Theactuation device may be disposed substantially inboard of the proximalend of the support structure.

The actuation device may comprise a linear actuator having a drivenelement and a base element, and the actuation device may be operable tomove the driven element linearly with respect to the base element. Thebase element may be coupled to the support head and the driven elementmay be coupled to the elongate arm.

The base element and/or the driven element may be disposed substantiallyinboard of the proximal end of the support structure.

The actuation device may be coupled with and may act on the elongate armvia a mechanical linkage.

The mechanical linkage may include a bell crank acting between theactuation device and the elongate arm. The bell crank may have arms ofunequal length, for example to provide a mechanical advantage. The bellcrank may have a mechanical advantage greater than unity.

At least some of the actuation devices may be arranged in pairs suchthat the actuation devices of each pair are staggered with respect toeach other. The first actuation device of the pair may be offset withrespect to the second in a direction towards the proximal end of thesupport head, and the first actuation device may be provided with anextended arm for connecting to the respective mechanical linkage.

The equipment may extend in a generally longitudinal applicationdirection from an actuation region where the actuation device is mountedto the support head to a tip region where lengths of fibre reinforcementmaterial are cut and applied to the article. The actuation region may belongitudinally spaced from the tip region. The cross-sectional profileof the equipment in a plane normal to the application direction may besmaller at the tip region than at the actuation region.

The support head may be moveable in at least one translationaldirection. The support head may be configured to rotate about alongitudinal rotation axis.

The invention may comprise any combination of the features and/orlimitations referred to herein, except combinations of such features asare mutually exclusive.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example,with reference to the accompanying drawings, in which:

FIG. 1 shows a composite material lay-up machine applying lengths ofelongate fibre reinforcement material to an article;

FIG. 2 is a perspective view of a support head and a cutting mechanismof the machine of FIG. 1;

FIG. 3 is a side-view of the support head and cutting mechanism of FIG.2;

FIG. 4 is a cut-away perspective view of the support head and cuttingmechanism of FIG. 2;

FIG. 5 is a perspective view of the cutting mechanism of FIG. 2 with aremovable guide channel cover in an open position;

FIG. 6 is an end view of an elongate arm of the cutting mechanism ofFIG. 2;

FIG. 7 is a cross-sectional side view of the cutting mechanism of FIG. 2having cut a length of elongate fibre reinforcement material;

FIG. 8 is an exploded perspective view of the end of the cuttingmechanism of FIG. 2 including a removable cassette;

FIG. 9 shows the tip region of the cutting mechanism of FIG. 2 withlengths of fibre reinforcement material passing out of the cassette;

FIG. 10 shows a single elongate arm of the cutting mechanism of FIG. 2together with the cassette;

FIG. 11 is an enlarged view of a cutting element and a counteractingelement of the cutting mechanism shown in FIG. 7; and

FIG. 12 is a perspective view of a part of the support head of FIG. 2together with a part of the cutting mechanism.

DETAILED DESCRIPTION

FIG. 1 shows a composite material lay-up machine 10 and a workpiece 12to which fibre composite material is being applied to form a compositematerial component, for example an aerospace component such as a wing.As shown in FIG. 1, the machine 10 performs a lay-up process in whichfibre composite tows 14 are applied to the workpiece 12. The machine 10comprises a base or gantry and a manipulation device 18 extending fromthe base or gantry, the manipulation device 18 supporting a support head20 which carries a cutting mechanism 22 at its distal end.

In use, the machine 10 feeds several tows 14 through the support head 20and the cutting mechanism 22 and applies the tows 14 to the workpiece 12using an applicator roller 24. At the end of an appropriate stage of thelay-up process, the tows 14 are cut by the cutting mechanism 22. In thisembodiment the tows 14 are pre-impregnated with matrix material such asepoxy resin, but in other embodiments each tow may comprise fibrereinforcement material only (often referred to as “dry fibre”) andmatrix material may be added subsequently.

In contrast to previously known lay-up machines, the machine 10 has acompact tip region 26 where the tow 14 is cut and applied to theworkpiece 12. The compact tip region 26 enables the machine 10 to lay-upcomponents having complex surface geometry since it can be manipulatedover regions of high curvature or other hard-to-access parts of thearticle, such as narrow recesses. As will be described below, thecompact tip region 26 benefits from placing bulkier components, such asactuators, away from the tip region 26, and from the provision of acutting mechanism 22 that can be actuated remotely from its cuttinglocation.

As shown in FIGS. 2 to 4, the support head 20 and the cutting mechanism22 extend in a generally longitudinal application direction from theproximal end of the support head, which in use is attached to themanipulation device 18 (not shown in FIGS. 2 to 4), to the distal tipregion 26 of the cutting mechanism 22 where the tow 14 is applied to theworkpiece 12 (not shown) and intermittently cut.

The support head 20 comprises two parallel triangular side plates 28extending from the proximal end of the support head 20 to the tip region26 of the machine. The side plates 28 are in the shape of an acuteisosceles triangle which gives the support head 20 and the cuttingmechanism 22 a tapered or converging profile. The support head 20further comprises upper and lower feed plates 30 supported between theside plates 28, both members 30 being arranged to convey tows 14 along aplurality of adjacent channels 32 towards the cutting mechanism 22. Inthis embodiment, each feed plate 30 has six adjacent channels 32 eachhaving a feed channel inlet and a feed channel outlet 33. Each feedplate 30 is provided with an outer cover plate 34 which in use enclosesthe tows 14 in the channels 32.

The feed plates 30 are also provided with conventional tow feedingequipment for feeding the tows 14 into and through the channels 32,which will not be described in detail. Briefly, the feed plates 30 areprovided with upper and lower redirecting rollers 36 extending behindthe support head and guiding tows 14 into the channels 32, and feedrollers 38 extending through corresponding gaps in the cover plates 34to drive the tows 14 through the channels 32.

As shown in FIG. 3, the inner side of each feed plate 30 is providedwith two rows of three actuator mounting points 40, 41 to whichactuators 84, 85 of the cutting mechanism 22 are mounted. As best shownin FIG. 4, the first row of actuator mounting points 40 islongitudinally offset from the second row of actuator mounting points41, and the respective mounting points of the two rows are alternatelylaterally offset with respect to one another such that actuators mountedthereto are staggered (note that FIG. 4 shows one representativeactuator 84, 85 only for each feed plate 30).

Referring now to FIGS. 3 and 4, the cutting mechanism 22 is disposedadjacent to the distal ends of the two feed plates 30 and between thetwo tip regions of the triangular side plates 28. The cutting mechanismcomprises a pivot axle 42 extending between the two side plates 28 and aplurality of elongate arms 44 mounted on the pivot axle 42 for pivotingmovement about a pivot axis A extending transverse to the applicationdirection. The pivot axle 42 slots into corresponding holes providedwithin the tip regions of the triangular side plates 28.

Each elongate arm 44 is in the form of a channel section having anoutwardly facing opening, and has an inwardly extending pivot attachmentportion 46 having a transversely extending hole which receives the pivotaxle 42. The pivot attachment portion 46 of each arm is approximatelyhalf way along the elongate arm, but slightly nearer to the distal end.In this embodiment, there are twelve elongate arms disposed in twoarrays in the form of rows: an upper row 46 comprising six elongate arms44 disposed side-by-side and a lower row comprising the remaining sixelongate arms 44 disposed side-by-side. The elongate arms 44 of the tworows are disposed on the pivot axle 42 in alternating sequence, suchthat the channel sections of the upper and lower arms 44 are laterallyoffset with respect to each other.

Each elongate arm 44 extends in a direction parallel to a plane which issubstantially perpendicular to the pivot axis A.

The channel section profile of each elongate arm forms a guide channel52 having a proximal guide channel inlet 54 (FIG. 5) and a distal guidechannel outlet 56 (FIG. 6). The elongate arms 44 are arranged such thatthe lateral positions of the guide channel inlets 54 correspond to thepositions of the feed channel outlets 33 (FIG. 2) of the support head20. There is only a short distance of longitudinal separation betweenthe feed channel outlets 33 and the guide channel inlets 54 such thatunsupported sections of the tows 14 are minimised. The guide channel 52is provided with a removable cover 58 such that the channel 52 isenclosed in use (FIG. 5). The removable cover 58 is pivotable at itsproximal end such that the guide channel 52 can be accessed, for examplefor maintenance.

As shown in FIG. 6, a cutting element 60 is attached to the distal endof each elongate arm 44. The cutting element 60 comprises a hardenedmaterial. In this embodiment, each elongate arm 44 has a slot forreceiving the cutting element 60 such that the outer surface of thecutting element 60 lies flush with the inner wall of the guide channel52, and such that a sharp cutting edge 62 of the cutting element 60forms the lip of the guide channel 52 at the guide channel outlet 56.The cutting element 60 is substantially cuboid in shape, but has atapered distal end face adjacent the cutting edge 62 that tapers awayfrom the cutting edge 62 in a direction towards the support head 20,such that the cutting edge 62 is the most distal part of the cuttingelement during a cutting stroke (as shown in FIG. 7). Similarly, the endface of the elongate arm 44 is tapered away from the cutting edge 62 ina direction towards the support head 20.

FIG. 7 shows the elongate arm 44 and further components of the cuttingmechanism 22 in cross-sectional side view. A guide channel insert 63 isdisposed in the distal end of each guide channel 52 and secured betweenthe two-side walls of the U-shaped guide channel 52 such that the guidechannel outlet 56 is in the form of a slot. The insert 63 defines theedge of the guide channel outlet 56 opposite the cutting edge 62 of thecutting element 60. In use, the removable cover 58 is secured to theinsert 63 by a bolt. FIG. 7 also shows a stop 64 which is arranged tocontact the inner surfaces of the ends of the elongate arms 44 when theyare rotated inwardly, and which prevents further rotation beyond thisstopped position. The stop 64 is mounted between the triangular sideplates 28 of the support head 20.

Referring now to FIGS. 8 to 11, the cutting mechanism 22 furthercomprises a cassette 65 which is removably mounted to the distal ends ofthe two triangular side plates 28. The cassette 65 comprises a cassetteplate 66 in which two rows of exit ducts 68 are formed, each duct 68having a duct inlet 70 and a duct outlet 72 through which the tow 14passes. The ducts 68 are arranged such that their lateral positionscorrespond to the positions of the respective guide channel outlets 56,and are provided to guide the tows 14 away from the cutting mechanismafter a cut is performed (as will be described below).

The duct outlets 72 are smaller than the duct inlets 70 such that theexit ducts 68 have a tapered profile which tapers along the applicationdirection. The duct outlets 72 are not narrower than the duct inlets 70(i.e. in a generally lateral direction parallel with the pivot axis A),but have a smaller depth (i.e. in a direction perpendicular to the pivotaxis A and the application direction).

Blade recesses 74 are formed in the inner surface of the cassette plate66 at positions extending over the exit duct inlets 70, such that theexit ducts 68 extend from these recesses 74 through to the outer surfaceof the cassette plate 66. Each blade recess 74 is arranged to receive acounteracting element in the form of a blade 76 such that the cuttingedge 78 of the counteracting element 76 is disposed immediately adjacentto the respective exit duct inlet 70. In this embodiment, sixcounteracting elements 76 are removably attached to each of an upper anda lower blade holder 80, which serve as a support strip to which theblades 76 can be removably mounted, and which can themselves beremovably mounted to the upper and lower surfaces of the cassette plate66 respectively.

As shown in FIG. 8, the upper row of exit ducts 68 are provided withdownwardly projecting counteracting elements 76 and the lower row ofexit ducts 68 are provided with upwardly projecting counteractingelements 76. The counteracting elements 76 are inclined to the generallylateral direction defined by the pivot axis A such that in a cuttingstroke the tow 14 is cut progressively from one side to the other in ascissor action. The cutting element 60 is composed of a harder materialthan the counteracting element 76 such that over time the counteractingelement 76, which is easily replaceable, is worn down in preference tothe cutting element 60.

As shown in FIG. 9, an exit guide roller 83 is mounted to the outersurface of the cassette plate 66 and is arranged to support the tows 14as they exit the exit ducts 68 and turn towards the applicator roller24. FIG. 9 also shows that the exit ducts 68 of the upper and lower rowsare laterally offset from each other such that the tows 14 exiting thecassette 65 are drawn onto the exit guide roller 83 alternately from thetwo rows. Correspondingly, the elongate arms 44 and feed channels 32 ofthe upper and lower rows of the cutting mechanism and support head 20are also laterally offset with respect to each other, as describedabove.

FIG. 10 shows a single elongate arm 44 together with the cassette 65. Asdescribed above, the elongate arm 44 and cassette 65 are arranged suchthat the guide channel outlet 56 of the guide channel 58 is laterallyaligned with an exit duct inlet 70 of the cassette 65. Correspondingly,the cutting element 60 is laterally aligned with the counteractingelement 76 disposed immediately adjacent to the duct 68. The cuttingelement 60 and the counteracting element 76 are configured to define anip between them, i.e. the space between the cutting element 60 and thecounteracting element 76 through which material to be cut is able topass and which closes as the material is cut in a cutting stroke.Specifically, the cutting edge 62 of the cutting element is arranged tofollow an arcuate path about the pivot axis A as the elongate arm 44 ispivoted in a cutting stroke. The cutting edge 78 of the counteractingelement 76 remains fixed relative the pivot axis A and the support head20 during a cutting stroke. The cutting element 60 and the counteractingelement 76 are arranged such that the cutting edge 78 of thecounteracting element 76 touches the arcuate path of the cutting edge 62of the cutting element 60. In other words, the arcuate path followed bythe cutting edge 62 of the cutting element defines an imaginary surfaceon which a line defined by the cutting edge 78 of the counteractingelement 76 lies.

Accordingly, the elongate arm 44 is arranged to be pivoted between anopen position in which the tow 14 can pass from the guide channel 52 andinto the exit duct 68 without being cut by the cutting element 60 and/orthe counteracting element 76, and a cut position in which the cuttingedges 62, 78 of the cutting element 60 and the counteracting element 76have passed each other so as to cut the tow 14 by a shearing, orscissoring, action, as shown in FIG. 11. In this embodiment, the distalend of the elongate arm 44 moves outwardly from an open position to acut position.

FIG. 11 shows the tip region 26 of the machine 10 in cross section,including the distal end of an elongate arm 44 and the cassette 65. Afibre composite tow 14 is shown within the guide channel 52 of theelongate arm 44. The elongate arm 44 is in a cut position in which thecutting edge 62 of the cutting element 60 has moved outwardly along anarcuate path past the cutting edge 78 of the counteracting element 76 tocut the fibre composite tow 14 in a cutting stroke by shearing. Thedistal portion of the cut tow 14 extends from the counteracting element76 through the exit duct 68 and onto the exit guide roller 83.

FIG. 11 also shows an adjustment screw 81 located within a tappedthrough-hole 82 in the cassette plate 66 adjacent to a counteractingelement 76. The adjustment screw 81 can be screwed through thethrough-hole 82 until it touches the counteracting element 76 in itsun-deflected position. The adjustment screw 81 may then be turnedfurther to resiliently deflect the cutting edge of the counteractingelement 76 to a deflected position, and may be screwed and unscrewed soas to fine-tune the alignment of the cutting edges of the cuttingelement 60 and the counteracting element 76. Since the counteractingelement 76 is resilient, it will return to its un-deflected position asthe adjustment screw 81 is unscrewed. This provides an adjustment meansfor adjusting the counteracting elements 76. As opposed to using anadjustment screw 81, in other embodiments the adjustment means maycomprise one or more springs which provide a force deflecting thecounteracting element 76 towards the cutting element 60.

Referring now to FIG. 12, the actuators 84, 85 are arranged to move thecutting elements 60 through a cutting stroke by acting on the elongatearms 44 via a mechanical linkage. Although FIG. 12 only shows actuators84, 85 for the lower row of elongate arms 44, it will be appreciatedthat a corresponding set of actuators 84, 85 are provided for the upperrow of elongate arms 44. The actuators may be of any suitable form, forexample electromagnetic, pneumatic or hydraulic actuators.

Each linear actuator 84, 85 comprises a base element 86 pivotablymounted to the inner side of the respective feed plate 30 of the supporthead 20 at the actuator mounting point 40, 41, and a driven element 88connected to the base element 86 by a drive rod 90 and linearly moveablewith respect to the base element 86. The cutting mechanism 22 isarranged to transmit the linear movement of the driven element 88 intopivoting movement of the elongate arm 44 (and so the cutting element 60)by way of a mechanical linkage comprising a bell crank 92. The bellcrank 92 is a substantially triangular element having three pivotableattachment points. The bell crank 92 is pivotably attached to thesupport head 20 at a first attachment point and to the driven element 88of the actuator 84 and the proximal end of the elongate arm 44 at secondand third pivotable attachment points respectively. The bell crank 92therefore has two substantially perpendicular arms to which the drivenelement 88 and the elongate member 44 are attached respectively. Theattachments are relatively positioned such that these arms are ofdifferent lengths. Specifically, the driven element 88 acts on the bellcrank 92 through a moment arm larger than that by which the bell crank92 acts on the elongate arm 44, such that the linear motion of thedriven element 88 is translated to pivoting movement of the elongate arm44 with a mechanical advantage. The mechanical advantage results in theforce applied to the elongate arm 44 by the bell crank 92 being greaterthan the force applied to the bell crank 92 by the actuation device 84(a mechanical advantage greater than one).

As described above, the actuator mounting points 40, 41 on the supporthead are provided over two rows such that the actuators 84 attachedthereto are staggered. This arrangement is clearly shown in FIG. 12, andrequires longer drive rods 90 for the actuators 85 mounted to theproximal row of actuator mounting points 41. These longer drive rods 90are sufficiently thin to pass between the adjacent actuators 84 mountedto the distal row of actuator mounting points 40. This staggeredarrangement allows the relatively bulky actuators 84 to be provided in arelatively narrow space.

In use, the manipulation device 18 moves the support head 20, whichcarries the cutting mechanism 22, relative to the workpiece 12 such thattows 14 fed through the support head 20 and cutting mechanism 22 to theapplicator roller 24 are applied to the surface of the workpiece 12 aspart of an automatically controlled lay-up procedure. In thisembodiment, the manipulation device 18 is capable of moving the supporthead 20 forward and back, an up and down, and the workpiece 12 can bemoved side-to-side, and rotate about three mutually perpendicular axes.This provides six degrees of freedom.

As a tow 14 is fed continuously through the cutting mechanism 22, therespective elongate arm 44 is in an open position in which the tow 14 isable to pass from the guide channel outlet 56 through the duct 68without being cut by the cutting element 60 or the counteracting element76, as described above.

At appropriate stages of the lay-up procedure, the machine 10 willdetermine that a fibre composite tow 14 is to be cut. The machine 10 isoperable to cut each tow 14 individually, sequentially orsimultaneously. Once it is determined that a particular fibre compositetow 14 is to be cut, the machine 10 activates the respective actuator84, 85 associated with the respective elongate arm 44 which conveys thetow 14 to a respective nip such that the actuator 84, 85 draws thedriven element 88 towards the base element 86. This movement causes thebell crank 92 to pivot relative the support head 20, which in turncauses the proximal end of the elongate arm 44 to move inwardly aboutthe pivot axis A. Due to the different arm lengths of the bell crank 92,the bell crank 92 has a mechanical advantage which results in therotational force applied to the elongate arm 44 being greater than thatapplied to the bell crank by the actuator 84, albeit for a smallerdisplacement (arc length) of the proximal end of the elongate arm 44.

The pivoting movement of the actuator 84 therefore causes the distal endof the elongate arm 44 to pivot outwardly, such that the cutting edge 62of the cutting element 60 cooperates with the cutting edge 78 of thecounteracting element 76 in a cutting stroke which severs the tow 14lying in the nip between them in a scissor-like shearing action.

Since the pivot axis A is closer to the distal end than the proximal ofthe elongate arm 44, the elongate arm 44 has a mechanical advantagewhich results in the force applied to the cutting element 60 at thedistal end of the elongate arm 44 during the cutting stroke beinggreater than the force applied to the proximal end of the elongate arm44 by the bell crank 92, albeit for a smaller displacement (arc length)of the distal end of the elongate arm 44 compared to the proximal end ofthe elongate arm 44.

Following the cutting stroke, the distal portion of the cut tow 14 maybe drawn away from the nip by subsequent motion of the support head 20over the workpiece 12, guided by the exit guide roller 83 and theapplicator roller 24. The respective actuator 84, 85 is then controlledto move the driven element 88 away from the base element 86, reversingthe pivoting motion of the elongate arm 44 and restoring the arm 44 toan open position in which the inner surface of the distal end of theelongate arm 44 rests on the stop 64.

The machine 10 may then control the feed rollers 38 to feed thecomposite tow 14 through the nip once more.

In this embodiment, each fibre composite tow 14 fed through the machine10 is associated with an elongate arm 44 coupled to a respectiveactuation device 84, 85. In order to sever a particular tow 14, therespective actuator 84, 85 is activated. However, in other embodimentstwo or more elongate arms 44 may be coupled to a single actuator 84 suchthat the single actuator 84 cuts two or more tows 14 simultaneously.

In this embodiment, the manipulation device 18 will stop movement of thesupport head 20 and cutting mechanism 22 relative to the workpiece 12when the tow 14 is to be cut, although it will be appreciated that inother embodiments the arm 18 may continue to move.

As described above, placing the actuation devices away from the tipregion allows the tip region to be compact. This has the benefit ofenabling the tip region of the machine to avoid collisions with theworkpiece in a lay-up process for a complex geometry workpiece, such asa workpiece having regions of high curvature, narrow recesses and otherhard-to-reach areas. The compact tip region allows the cutting elementand counteracting element (i.e. the cutting location) to be near to theapplicator roller, which may enable a shorter minimum tow length thanpreviously achievable.

The mechanical advantage of the bell crank and the elongate arm, has theeffect that a high cutting force can be achieved between the cuttingelement and the counteracting element during a cutting stroke whilst alower force is applied at the actuator. The mechanical advantage of themechanical linkage may therefore reduce the need for bulky actuatorswith high force ratings.

The removable cassette allows for easy maintenance and replacement ofthe cutting parts. The cassette can be swiftly removed and thecounteracting elements replaced, either individually, as an entire rowof counteracting elements mounted on a countering element holder, oralternatively the entire cassette itself could be replaced. Further, thecassette allows the cutting elements coupled to the elongate arms to beeasily accessed and replaced, if necessary. Accordingly, the removablecassette allows rapid maintenance with minimal equipment downtime.

Although embodiments of the invention have been described by referenceto pre-impregnated fibre composite tows, it will be appreciated that theinvention is equally applicable to the application and cutting of otherforms of fibre composite and/or fibre reinforcement material. Forexample, the invention is equally applicable to the application andcutting of fibre composite or fibre reinforcement material tape. Thetape may comprise unidirectional carbon fibre, and may or may not bepre-impregnated with matrix material. Further, it will be appreciatedthat in the foregoing description, the term “tow” is equally applicableto a plurality of individual strands of dry fibre reinforcement/fibrecomposite material and to a narrow tape of fibre reinforcement/fibrecomposite material.

For the avoidance of doubt, the expression “composite material” isintended to cover both reinforcement material for use in making acomposite component (e.g. dry composite fibres), and composite materialcomprising both reinforcement material and matrix material.

Although embodiments of the invention have been described in which thesupport head moves forwards and backwards, and up and down, and theworkpiece moves side-to-side and rotationally about three axes, it willbe appreciated that in other embodiments the support head and workpiecemay be capable of other movements. For example, the workpiece may becapable of moving forwards and backwards, and side-to-side, whilst thesupport head may be capable of moving up and down, and rotationallyabout three mutually perpendicular axes. This arrangement would alsoprovide six degrees of freedom. Of course, it is possible that less ormore than six degrees of freedom are provided. The workpiece maycomprise a mandrel or it may be mounted on a mandrel.

Further, although the invention has been described in the context of anAutomatic Fibre Placement (AFP) process, it will be appreciated that theinvention is equally applicable to other composite lay-up processesincluding Automatic Tape Laying (ATL) and automatic fibre winding.

Although the embodiments of the invention which have been describedcomprise substantially linearly extending elongate arms, it will beappreciated that in other embodiments the elongate arms may be curved orotherwise non-linear, whilst still extending in a plane perpendicular tothe pivot axis. In some embodiments it may be possible to integrallyform the or each bell crank with the respective elongate arm.

Although the embodiments of the invention which have been describedcomprise a single pivot axle and a single corresponding pivot axis, itwill be appreciated that in other embodiments there may be a pluralityof pivot axes. For example, there may be a separate pivot axle for eachrow of side-by-side elongate arms. Further, a subset of the elongatearms or individual elongate arms may have their own pivot axis. Pivotaxes could be longitudinally separated from each other and/or may beabove and below one another (i.e. parallel but separated in a directionperpendicular to a pivot axis and the generally longitudinal applicationdirection).

In the above description, the generally longitudinally extendingapplication direction relates to the overall proximal to distal orback-to-front direction of the support head and cutting mechanism. It isreferred to as the application direction because in the embodimentsdescribed it is generally the direction along which fibre reinforcementmaterial is fed through the support head and cutting mechanism to beapplied to a workpiece. The pivot axis defines a direction referred tofor convenience as generally horizontal or lateral, although it is notnecessary for the machine to be oriented in use such that the pivot axisremains horizontal. Similarly, references such as “vertical” “upper” and“lower” and the like relate to a direction perpendicular to the pivotaxis and the application direction. Again, it is not necessary for themachine to be oriented in use such that “upper” components are alwaysabove “lower” components, since the support head and cutting mechanismmay be rotated to adopt any configuration. The terminology employedreflects the position of the equipment shown in FIG. 2 and is intendedto establish a useful frame of reference in the foregoing description.

Although it has been described that the cutting edge of thecounteracting element lies on or touches an imaginary cylindricalsurface defined by the arcuate movement of the cutting edge of thecutting element, it will be appreciated that this alignment need not beexact. In particular, it will be appreciated that where thecounteracting element is a planar blade and the cutting edge of thecounteracting element is inclined it may not precisely lie on or touchthe imaginary cylindrical surface.

The radius of the arcuate path followed by the cutting edge of thecutting element depends on the distance between the cutting edge and thepivot axis. In most embodiments, this radius will be significantlylarger than the arc length of a cutting stroke, and therefore thearcuate movement of the cutting edge of the cutting element may beapproximated as linear movement.

Although embodiments of the invention have been described in which thefibre composite material is cut by a shearing action, it will beappreciated that in other embodiments, the cutting mechanism may bearranged to cut the fibre composite material by another cutting process,for example by anvil cutting in which a straight cutting element bearsdown on an anvil to cut material disposed between them.

REFERENCE NUMERALS

-   Composite material lay-up machine 10-   Composite material workpiece 12-   Fibre composite material 14-   Manipulation device 18-   Support head 20-   Cutting mechanism 22-   Applicator roller 24-   Tip region 26-   Triangular side plates 28-   Feed plates 30-   Feed channels in feed plates 32-   Feed channel outlet 33-   Outer cover plate 34-   Redirecting rollers 36-   Feed rollers 38-   Actuator mounting points (first row) 40-   Actuator mounting points (second row) 41-   Pivot axle 42-   Elongate arm 44-   Pivot attachment of elongate arm 46-   Upper row of elongate arms 48-   Lower row of elongate arms 50-   Guide channel in elongate arm 52-   Guide channel inlet 54-   Guide channel outlet 56-   Removable cover of guide channel 58-   Cutting element 60-   Cutting edge of cutting element 62-   Guide channel insert 63-   Stop 64-   Cassette 65-   Cassette plate 66-   Exit duct 68-   Exit duct inlet 70-   Exit duct outlet 72-   Blade recess 74-   Counteracting element (or counteracting element) 76-   Cutting edge of the counteracting element 78-   Counteracting element holder 80-   Adjustment screw 81-   Tapped through-hole 82-   Exit guide roller 83-   Actuator (first row) 84-   Actuator (second row) 85-   Base element of an actuator 86-   Driven element of an actuator 88-   Drive rod of an actuator 90-   Bell crank 92

1. Composite material lay-up equipment for applying a plurality ofindividual lengths of elongate fibre reinforcement material to anarticle, the equipment comprising: a support head; a cutting mechanismcarried by the support head for severing a plurality of individuallengths of elongate fibre reinforcement material, the cutting mechanismcomprising: a plurality of cutting elements coupled to and moveable withrespect to the support head; and a cassette removably attached to thesupport head and having a plurality of corresponding counteractingelements statically mounted thereto; wherein each cutting element isdisplaceable relative to the corresponding counteracting element toperform a cutting stroke in which the respective cutting andcounteracting elements cooperate to sever a length of elongate fibrereinforcement material extending through the nip formed between them. 2.Composite material lay-up equipment according to claim 1, wherein thecounteracting elements are removably mounted to the cassette. 3.Composite material lay-up equipment according to claim 1 or 2, whereinthe cutting elements are composed of a harder material than thecounteracting elements.
 4. Composite material lay-up equipment accordingto any one of the preceding claims, wherein the cassette comprises aplurality of guide ducts, each counteracting element disposed adjacentto a respective guide duct which is arranged to guide the fibrereinforcement material away from the nip between the counteractingelement and the corresponding cutting element.
 5. Composite materiallay-up equipment according to claim 4, wherein each guide duct has aprofile which tapers from a duct inlet opening to a duct outlet opening.6. Composite material lay-up equipment according to any one of thepreceding claims, wherein the cassette comprises an exit guide rollerarranged to guide the individual lengths of fibre reinforcement materialaway from the cassette.
 7. Composite material lay-up equipment accordingto any one of the preceding claims, wherein each counteracting elementhas a cutting edge and wherein each cutting element has a cutting edge.8. Composite material lay-up equipment according to claim 7, wherein thecutting edge of each cutting element is inclined relative to the cuttingedge of the corresponding counteracting element such that in a cuttingstroke the cutting element and the counteracting element cooperate in ascissor action.
 9. Composite material lay-up equipment according toclaim 7 or 8, wherein the cutting edge of each counteracting elementtouches the path followed by the cutting edge of the correspondingcutting element in a cutting stroke.
 10. Composite material lay-upequipment according to any one of claims 7 to 9, wherein thecounteracting elements are substantially planar.
 11. Composite materiallay-up equipment according to claim 10, wherein the cassette furthercomprises adjustment means capable of resiliently deflecting the cuttingedge of each counteracting element towards the corresponding cuttingelement.
 12. Composite material lay-up equipment according to claim 11,wherein the adjustment means comprises a plurality of adjustment screws,one for each counteracting element, wherein each adjustment screw can beturned so as to act on its counteracting element thereby deflecting thecutting edge.
 13. Composite material lay-up equipment according to anyone of claims 7 to 12, wherein the plurality of counteracting elementsare arranged side-by-side in at least one row.
 14. Composite materiallay-up equipment according to claim 13, wherein there are two rows ofcounteracting elements.
 15. Composite material lay-up equipmentaccording to claim 14, wherein the cutting edges of the first row ofcounteracting elements face the cutting edges of the second row ofcounteracting elements.
 16. Composite material lay-up equipmentaccording to any one of claims 7 to 15, wherein at least twocounteracting elements are mounted to the cassette by a holder which isremovably mounted to the cassette, and wherein each of the at least twocounteracting elements is individually removably mounted to the holder.17. Composite material lay-up equipment according to claim 16 whendependent on claim 14, wherein there are two holders and wherein eachrow of counteracting elements corresponds to a respective holder. 18.Composite material lay-up equipment according to any one of claims 7 to17, wherein each cutting element is coupled to a separate elongate armwhich is pivotable about a pivot axis, wherein the elongate arms arearranged to move the cutting elements along an arcuate path during acutting stroke.
 19. Composite material lay-up equipment according toclaim 18, wherein the cutting edge of each cutting element issubstantially parallel to the corresponding pivot axis, and wherein thecutting edge of each counteracting element is inclined with respect tothe corresponding pivot axis.
 20. Composite material lay-up equipmentfor applying a plurality of individual lengths of elongate fibrereinforcement material to an article, the equipment comprising: asupport head; a cutting mechanism carried by the support head forsevering a plurality of individual lengths of elongate fibrereinforcement material, the cutting mechanism comprising: a plurality ofcutting elements coupled to and moveable with respect to the supporthead; and a cassette removably attached to the support head and having aplurality of corresponding counteracting elements, each having a cuttingedge, statically mounted thereto, wherein the plurality of counteractingelements are removably mounted to the cassette, and wherein the cassettecomprises: a plurality of guide ducts each having each a profile whichtapers from a duct inlet opening to a duct outlet opening, eachcounteracting element disposed adjacent to a respective guide duct whichis arranged to guide the fibre reinforcement material away from the nipbetween the counteracting element and the corresponding cutting element;and adjustment means capable of resiliently deflecting the cutting edgeof each counteracting element towards the corresponding cutting element;wherein each cutting element is displaceable relative to thecorresponding counteracting element to perform a cutting stroke in whichthe respective cutting and counteracting elements cooperate to sever alength of elongate fibre reinforcement material extending through thenip formed between them.
 21. Composite material lay-up equipmentsubstantially as described herein with reference to the accompanyingdrawings.